The present invention relates generally to a sheet conveying apparatus, for example, for conveying newspapers, and more particularly to a sheet conveying apparatus having pockets moving on a track.
U.S. Pat. No. 5,343,806 discloses a swivellable pre-gripper of a sheet-fed printing press and is cited as background on grippers in general.
U.S. Pat. Nos. 4,723,770 and 6,311,968 show top grippers for holding open a first set of printed materials so that a second set printed material may be inserted into the first set of printed materials. The rotational axis of these top grippers is fixed with respect to the pocket. U.S. Pat. Nos. 4,723,770, 5,343,806 and 6,311,968 are incorporated by reference herein.
To adjust pocket sizes, it has been known to alter the position of a bottom stop.
An object of the present invention is to permit for various paper sizes to be better accommodated in moving pockets. Another alternate or additional object of the present invention is to improve the adjustability of pockets.
The present invention provides a sheet material conveying apparatus comprising:
at least one pocket running along a track, the pocket including a base section for receiving sheet material and an upper section including at least one upper gripper for holding an edge of the sheet material, the at least one upper gripper being movable between a gripping position and a non-gripping position, and the upper section being movable with respect to the base section to alter a distance of the at least one upper gripper with respect to the base section.
By altering the top gripper position with respect to the base section, varying product widths can be accommodated without having to adjust a pocket bottom or stop. In addition, better accuracy of the top gripper placement can be achieved with respect to the front of the pocket.
Preferably, the upper gripper is rotatable about an axis in the upper section.
The pocket preferably includes a setting mechanism for moving the upper section with respect to the base section.
The setting mechanism preferably includes a cam follower connected to one of the upper section and the base section. The cam follower may be connected to a shaft of the setting mechanism, with rotation of the shaft setting the distance between the upper section and base section.
Preferably, a latch can be provided to hold the setting mechanism at the distance set by the cam follower.
Preferably, the upper gripper is rotatable but translationally fixed with respect to the upper section.
The present invention also provides a method for setting a distance of a top gripper of a pocket comprising the steps of:
moving a plurality of pockets along a track;
gripping sheet products by rotating the upper gripper about a rotational axis; and
adjusting the distance of the rotational axis of the top gripper from a base section of the pocket.
Preferably, the adjusting step occurs concurrently with the moving step, for example through a cam/cam follower interaction.